Method for simulating a movement by means of an acoustic reproduction device, and sound reproduction arrangement therefor

ABSTRACT

A system and method is disclosed for simulating a movement in a predetermined direction relative to a reference point in the surroundings of an acoustic reproduction device, wherein at least two virtual sound sources are produced via the acoustic reproduction device. The acoustic reproduction device is preferably controlled using a control unit, wherein the control unit controls the repeated movement of the at least two virtual sound sources in succession from a predetermined starting point to a predetermined ending point, and back again to the starting point, and controlling a direction of movement for the at least two virtual sound sources such that the direction of movement coincides with the direction of the movement to be simulated.

TECHNICAL FIELD

The present disclosure relates to a system and method for simulating amovement in a predetermined direction relative to a reference point inthe surroundings of an acoustic reproduction device, and to a soundreproduction arrangement for carrying out such a method.

BACKGROUND

A moving performance from sound sources is known in principle in theprior art. In such cases, a person in the surroundings of the acousticreproduction device has movement through space simulated by virtue of asound source produced by the acoustic reproduction device movingrelative to the person in a predetermined direction of movement.

An example that illustrates this concept is the movement of a soundsource from a first loudspeaker to a second loudspeaker, that is placedat a distance from the first loudspeaker, by means of an acousticreproduction device.

In the prior art, “virtual sound sources” are typically implementedwithin the overall system. A virtual sound source is implemented bymeans of suitable superimposition of sound signals, so that a personhearing these signals is given the impression that the sound signalsheard came from a particular point in space in his or her surroundings.Further details of virtual sound sources may be found in the articletitled: “An Interactive Virtual-Environment Generator for PsychoacousticResearch, I: Architecture and Implementation” by J. Blauert et al. inACUSTICA/Acta Acustica” 86, 2000, pp. 94-102. Furthermore, the articletitled: “Binaural Room Scanning—A new Tool for Acoustic andPsychoacoustic Research” by P. Mackensen et al., which appeared in theDAGA 1999 conference report (annual conference of the German acousticssociety), describes the movement of a virtual sound source. The contentsof both articles are hereby incorporated by reference in their entirety.

A method for simulating a movement by means of a virtual sound sourcehas the drawback that this sound source needs to move on a circularpath, for example, in order to indicate a movement in a particulardirection continuously. If the sound source is moving in a straightline, the sound source will become increasingly distant from the person,which means that at a particular time it is no longer possible toindicate the movement to the person.

SUMMARY

In light of the above, one object of the present disclosure is based onthe object of using an acoustic reproduction device to simulate amovement in a predetermined direction, with a generated sound source toboth to simulate a movement, and to remain essentially fixed in space,depending on the application.

This object is achieved by a method for simulating a movement in apredetermined direction relative to a reference point in thesurroundings of an acoustic reproduction device, having the followingsteps:

a) the acoustic reproduction device is provided in order to produce atleast two virtual sound sources,

b) the acoustic reproduction device is controlled using a control unitthat is designed for the repeated movement of the at least two virtualsound sources in succession from a predetermined starting point to apredetermined ending point, and from there abruptly back to the startingpoint, where a direction of movement for the at least two virtual soundsources coincides with the direction of the movement which is to besimulated.

The effect of the proposed method is that a person who is at thereference point perceives the at least two virtual sound sources as asingle sound source which is essentially at a fixed location butsimulates movement from the starting point to the ending point.

Preferably, the control in step b) is executed such that a movement bythe at least two virtual sound sources is effected essentially at rightangles to a connecting line between the reference point and a point inthe center between the starting point and the ending point of themovement by the at least two virtual sound sources. Accordingly, it ispossible to ensure particularly clear perception of the movement whenthe aim is to indicate to the person a particular direction of movementby means of the acoustic reproduction device.

If the method is used to indicate to a person the directions “left” or“right” in relation to the person's head, for example, then the methodcan be carried out in the described manner, with the at least twovirtual sound sources in this case being moved either from right toleft, and abruptly back again, or from left to right and abruptly backagain by means of the control unit. In this context, the mid-point willbe situated between the starting point and the ending point of themovement by the at least two virtual sound sources approximately in thecenter of the person's field of vision.

Alternatively, however, it is also possible to use the method tosimulate movements which are at an angle to the connecting line betweenthe reference point and the mid-point between the starting point and theending point. If the method is used in combination with a navigationsystem in a motor vehicle, for example, the path between the startingpoint and the ending point may correspond to a direction which isprescribed by the navigation system. Depending on the respective currentwhereabouts of the motor vehicle, the path of movement for the at leasttwo virtual sound sources can be adapted such that the direction oftravel which is to be selected for the motor vehicle is always indicatedaudibly.

In one exemplary embodiment, the control in step b) takes place suchthat for each virtual sound source there is an increase in the soundintensity from the starting point to the mid-point and a decrease in thesound intensity from the mid-point to the ending point. This measurecontributes to giving the person who perceives the acoustic reproductiondevice the impression that there is only a single, essentiallyfixed-location sound source. In particular, the sound intensity canincrease at a constant rate up to the mid-point and can decrease at thesame rate from the mid-point to the ending point.

To simulate a uniform movement, it is preferable for a 30 speed ofmovement for the at least two virtual sound sources to be constant instep b).

To improve the perception properties of the acoustic reproductiondevice, there should preferably be at least four virtual sound sourcesused which are controlled in the manner explained with reference to theaforementioned at least two virtual sound sources.

The aforementioned object is also achieved by a sound reproductionarrangement having an acoustic reproduction apparatus for simulating amovement in a predetermined direction relative to a reference point inthe surroundings of an acoustic reproduction device. The soundreproduction arrangement further produces at least two virtual soundsources and includes a control unit that is designed for the repeatedmovement of the at least two virtual sound sources in succession from apredetermined starting point to a predetermined ending point, and fromthere abruptly back to the starting point, where a direction of movementfor the at least two virtual sound sources coincides with the directionof the movement which is to be simulated.

BRIEF DESCRIPTION OF THE DRAWINGS

The various objects, advantages and novel features of the presentdisclosure will be more readily apprehended from the following detaileddescription when read in conjunction with the enclosed drawing, inwhich:

FIG. 1 illustrates a time sequence for arrangements comprising aplurality of virtual sound sources in relation to a person in thesurroundings of the sound sources to simulate a movement for the person.

DETAILED DESCRIPTION

With regard to FIG. 1, it should be noted that the distance shownbetween virtual sound sources VS A, VS B, VS C and VS D (i.e., fourvirtual sound sources), and a person, who is represented by an ellipseas a stylized view from above his/her head, need not be comparable withactual distances. In certain instances of application, the distance willbe very short, as suggested by the drawing, but it is also possible forthe virtual sound sources VS A, VS B VS C and VS D to be at aconsiderable distance from the person P.

In the exemplary embodiment shown, four virtual sound sources VS A, VSB, VS C and VS D are shown both at a time T=0 s and at further times,where T=2 s, T=4 s and T=6 s. This arrangement illustrates how therelative movement of the individual virtual sound sources VS A, VS B, VSC and VS D relative to the person is executed as a function of time.

At the time T=0 s, the virtual sound sources VS A, VS B, VS C and VS Dare in an initial formation, where they are situated on a common line,illustrated in the present exemplary embodiment as a straight line. Atthe time T=2 s, all of the virtual sound sources have moved one intervalto the left at the same speed, this movement continuing up to a time T=4s.

At the time T=6 s, the leading virtual sound source VS A has beenabruptly moved behind the virtual sound source VS D, which means thatthe virtual sound source VS B is now the leading one and the virtualsound source VS A is now the lagging sound source.

Overall, a movement from right to left in the drawing is thus obtainedfor all of the virtual sound sources VS A, VS B, VS C and VS D. As soonas the virtual sound source VS B, which is initially arranged behind thevirtual sound source VS A, has reached the original position CT=0 s ofthe virtual sound source VS A in the course of time, the virtual soundsource VS A is abruptly moved to the end of the row of virtual soundsources VS A, VS B, VS C, VS D.

The path to be covered by each virtual sound source VS A, VS B, VS C andVS D in order to simulate a movement in the direction of an arrow B inthe figure for the person P is identical. This path is defined by astarting point and an ending point. The starting point is defined as apoint in space to which each of the virtual sound sources VS A, VS B, VSC, VS D are abruptly returned when they have reached the ending point onthe path. When one of the virtual sound sources VS A, VS B, VS C and VSD is abruptly returned to the starting point SP, its sound intensity ispreferably 0, which means that no influence is exerted on the acousticperception by the person P as a result of returning the virtual soundsources VS A, VS B, VS C, VS D. In the case of impaired embodiments, thestarting point SP and the ending point EP for the path which is to becovered may also vary.

A mid-point MP on the path covered by the virtual sound sources VS A, VSB, VS C and VS D is situated approximately in the direction of ahorizontal mid-axis in the field of vision of the person P. The pathcovered runs approximately at right angles to a connecting line Vbetween the mid-point on the path and the person P, who defines areference point.

The movement of the virtual sound sources VS A, VS B, VS C and VS D iscontrolled by a control unit (not shown) which is connected to anacoustic reproduction device (not shown), which may be headphones or aloudspeaker arrangement, for example.

The acoustic reproduction device and the control unit together form asound reproduction arrangement that is suitable for carrying out thepresently disclosed method. The control unit tracks the position of eachof the virtual sound sources VS A, VS B, VS C and VS D at a particulartime. Depending on the respective position, the control unit determinesthe intensity of the sound signal that is emitted by a virtual soundsource VS A, VS B, VS C and VS D of interest. From the starting point SPon the right-hand side of FIG. 1, the intensity increases up to theaforementioned mid-point MP, after which it decreases down to the endingpoint EP. The sound intensity increases and decreases at the sameconstant rate. This configuration has the advantage that a person P willperceive the sound source arrangement, which is obtained from the foursuccessively arranged virtual sound sources VS A, VS B, VS C and VS D,to be a single sound source which is at a fixed location but whichsimulates a movement from right to left. In particular, a virtual soundsource situated at the left-hand edge is moved abruptly when itsintensity has reached its minimum.

Regarding the audio signal to be emitted by the virtual sound sources VSA, VS B, VS C and VS D, it is also possible to use white noise (MLSsignal) as a sound signal, for example, as long as the emitted audiosignals have a bandwidth that allows the sound signals to be localized.Alternatively, the virtual sound sources VS A, VS B, VS C and VS D mayalso be voice signals or “auditory icons”, which are naturally orsynthetically generated sound signals which have an associated functionand which are related to this function by the person P as intuitively aspossible. It is preferable that all of the virtual sound sources VS A,VS B, VS C and VS D emit the same audio signal, possibly with changingintensity.

The text below describes a few exemplary alternate embodiments of theabove-described method and of the associated sound 35 reproductionarrangement:

APPLICATION EXAMPLE 1

A person uses a navigation system that is installed in a motor vehicle.When the navigation system uses a voice output to suggest to the personthat he turn off to the left after 500 meters, for example, the voiceoutput is played back such that the four virtual sound sources VS A, VSB, VS C and VS D move in the desired direction, in the present case tothe left.

APPLICATION EXAMPLE 2

A person uses a location-related service using a mobile telephone. Inthis case, he/she uses stereo headphones. The location-related serviceindicates to the person that he needs to move upward in order to find adepartment which he is looking for within a shop. In this case, the fourvirtual sound sources are moved by means of the control unit such that amovement upward is simulated. The audio signal played back in this case,for example “Please move to the next floor up”, then forms the outputsignal from the virtual sound sources VS A, VS B, VS C and VS D.

From the movement of the virtual sound sources VS A, VS B, VS C and VSD, the person can intuitively tell that he needs to go to the next floorup, for example using an escalator.

APPLICATION EXAMPLE 3

A mobile telephone may be configured to show user menus virtually inspace. In this case, the person using the mobile telephone is visuallygiven the impression that more deeply nested menu entries are furtheraway than the top menu level. The person is thus able to obtain animpression of what is hidden behind a menu item on the top level, forexample, and can intuitively move through this virtual spatialrepresentation of menus.

To make navigation in a three-dimensional user menu of this typeintuitive, it is possible to use “three-dimensional audio icons”. Usingthese icons, it is possible to convert a movement by the user into amovement by the virtual sound sources VS A, VS B, VS C and VS D and torender it audible to the user. In this way, he can find his way aroundbetter in the three-dimensional virtual spatial representation of theuser menus.

APPLICATION EXAMPLE 4

In the case of a game implemented on a mobile telephone, the aim is togive a person the impression that he/she is moving through a virtualworld. In this context, the person's speed of movement needs to change.It is often difficult to clarify the change in the speed of movementsolely by means of a visual impression which the person gets from themobile telephone's display panel, for example.

In this case, parallel performance of the method described above allowsthe movement to be clarified by virtue of sound effects which are playedremaining at a fixed location in space, on the one hand, while theperson perceives an apparent movement, on the other. In this way, it ispossible to “simulate” the impression of different speeds of movement,for example, for the person.

In this exemplary embodiment, the physical positions of the startingpoint SP and of the ending point EP over time are not fixed but rathertime-dependent. This means that the distance between the virtual soundsources VS A, VS B, VS C, VS D and the person is increased in thepresent case.

In further application examples, it may also be appropriate for the pathcovered by the virtual sound sources VS A, VS B, VS C, VS D to bevariable over time, but with each of the virtual sound sources VS A, VSB, VS C and VS D continuing to move along the path and to make theabrupt return movement, in particular.

The above description and drawings are only to be consideredillustrative of exemplary embodiments, which achieve the features andadvantages of the invention. Modification and substitutions to specificprocess conditions and structures can be made without departing from thespirit and scope of the invention. Accordingly, the invention is not tobe considered as being limited by the foregoing description anddrawings, but is only limited by the scope of the appended claims.

1-9. (canceled)
 10. A method for simulating a movement in apredetermined direction relative to a reference point in thesurroundings of an acoustic reproduction device, the method comprisingthe steps of: a) producing at least two virtual sound sources via theacoustic reproduction device; and b) controlling the acousticreproduction device using a control unit, wherein said control unitcontrols the repeated movement of the at least two virtual sound sourcesin succession from a predetermined starting point to a predeterminedending point, and back again to the starting point, and controlling adirection of movement for the at least two virtual sound sources suchthat the direction of movement coincides with the direction of themovement to be simulated.
 11. The method according to claim 10, whereinstep b) is performed such that a movement by the at least two virtualsound sources is effected essentially at right angles to a connectingline between a reference point and a point in the center between thestarting point and the ending point of the movement by the at least twovirtual sound sources.
 12. The method according to claim 11, whereinstep b) is performed such that, for each virtual sound source, there isan increase in the sound intensity from the starting point to themid-point, and a decrease in the sound intensity from the mid-point tothe ending point.
 13. The method according to claim 10, wherein a speedof movement for the at least two virtual sound sources is constant. 14.The method according to claim 10, further comprising: producing at leasttwo additional virtual sound sources via the acoustic reproductiondevice, wherein said control unit controls the repeated movement of theat least two additional virtual sound sources in succession from apredetermined starting point to a predetermined ending point, and backagain to the starting point, and controlling a direction of movement forthe at least two additional virtual sound sources such that thedirection of movement coincides with the direction of the movement to besimulated
 15. A sound reproduction system, comprising: an acousticreproduction apparatus for simulating a movement in a predetermineddirection relative to a reference point in the surroundings of anacoustic reproduction device and for producing at least two virtualsound sources; and a control unit that processes the repeated movementof the at least two virtual sound sources in succession from apredetermined starting point to a predetermined ending point and backagain to the starting point, where a direction of movement for the atleast two virtual sound sources coincides with the direction of themovement which is to be simulated.
 16. The sound reproduction system ofclaim 15, wherein the control unit has a position detection device fordetecting the position of the virtual sound sources and further controlsthe intensity of each virtual sound source on the basis of its positionbetween the starting point and the ending point.
 17. The soundreproduction system of claim 15, wherein the control unit effects amovement by the at least two virtual sound sources substantially atright angles to a connecting line between the reference point and apoint in the center between the starting point and the ending point ofthe movement by the at least two virtual sound sources.
 18. The soundreproduction system of claim 15, wherein the control unit effects anincrease in the sound intensity from the starting point to the mid-pointand a decrease in the sound intensity from the mid-point to the endingpoint for each virtual sound source.